January 31, 2011

No more left turn on a solid green light?

The days of turning left at a signal with a solid green light may be numbered. Federal officials are urging cities to replace traffic signals at intersections where a left turn is allowed after yielding to oncoming traffic. Instead of using a green ball-shaped signal, government officials want to use a flashing yellow arrow.

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This is unacceptable, the present traffic signals are not dependable. Many intersections have green arrows for left hand turns and these in some cases should be changed to left turns on a green signal light. I have sat at many signals that failed to function properly not allowing traffic to flow in the programed sequence. The federal government has no business in dictacing traffic control these people can hardly walk and chew gum in the same moment.

John, I don't think you understand what this proposal will do. All it is doing is changing the permissive left signal display from a solid green light to a flashing yellow signal. It's just a display change, not a signal cycle programming change. Research has shown that people inherently understand the flashing yellow arrow better than a solid green signal with regards to indicating that left turning traffic must yield. And the feds do have business with this because traffic control devices are coordinated across the US to prevent confusion when drivers travel between states. Even the state law regarding traffic signs and signals says that the state sign manual must comform to the federal standards.

"Riding in his green Saab, we glide into Drachten, a 17th-century village that has grown into a bustling town of more than 40,000. We pass by the performing arts center, and suddenly, there it is: the Intersection. It's the confluence of two busy two-lane roads that handle 20,000 cars a day, plus thousands of bicyclists and pedestrians. Several years ago, Monderman ripped out all the traditional instruments used by traffic engineers to influence driver behavior - traffic lights, road markings, and some pedestrian crossings - and in their place created a roundabout, or traffic circle. The circle is remarkable for what it doesn't contain: signs or signals telling drivers how fast to go, who has the right-of-way, or how to behave. There are no lane markers or curbs separating street and sidewalk, so it's unclear exactly where the car zone ends and the pedestrian zone begins. To an approaching driver, the intersection is utterly ambiguous - and that's the point.

Monderman and I stand in silence by the side of the road a few minutes, watching the stream of motorists, cyclists, and pedestrians make their way through the circle, a giant concrete mixing bowl of transport. Somehow it all works. The drivers slow to gauge the intentions of crossing bicyclists and walkers. Negotiations over right-of-way are made through fleeting eye contact. Remarkably, traffic moves smoothly around the circle with hardly a brake screeching, horn honking, or obscene gesture. "I love it!" Monderman says at last. "Pedestrians and cyclists used to avoid this place, but now, as you see, the cars look out for the cyclists, the cyclists look out for the pedestrians, and everyone looks out for each other. You can't expect traffic signs and street markings to encourage that sort of behavior. You have to build it into the design of the road.""http://www.wired.com/wired/archive/12.12/traffic.html